Harvey wisely and sensitively acknowledges this:
I recognize that there will be some reading this who can’t imagine the kind of physical relationship Paul indicates. For you, intimacy with your spouse may be intertwined with a sense of apprehension, rejection, and shame. This is a real challenge in many marriages that cannot be simply overlooked. (157)
Many of us shut down when wounded, or withdraw when discouraged, or are tempted to manipulate our spouse by using the body as a bargaining tool. We can be tempted with “solo sex” through fantasy, pornography, and/or masturbation. (159-160)
I offer no trite or flippant "solutions." I only remind you that you are not alone (God is with you and you are in quite a vast company of those who have struggled), God is willing and God is able to give grace and help.
Which is why the last point is so important…